Pathways to Elastic Turbulence in Giant Micelles Through Curvature Ratios in Taylor-Couette Flow

Fuente: arXiv
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Autores principales: Yang, Xiaoxiao, Marin, Darius, Py, Charlotte, Cardoso, Olivier, Lindner, Anke, Lerouge, Sandra
Formato: Preprint
Publicado: 2025
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author Yang, Xiaoxiao
Marin, Darius
Py, Charlotte
Cardoso, Olivier
Lindner, Anke
Lerouge, Sandra
author_facet Yang, Xiaoxiao
Marin, Darius
Py, Charlotte
Cardoso, Olivier
Lindner, Anke
Lerouge, Sandra
contents In the past fifteen years, flow instabilities reminiscent of the Taylor-like instabilities driven by hoop stresses, have been observed in wormlike micelles based on surfactant molecules. In particular, purely elastic instabilities and turbulence have been shown to develop on top of shear banding, a type of flow specific to the semi-dilute and concentrated regimes. These instabilities have been identified as the origin of the large body of data showing complex spatio-temporal fluctuations, collected in shear-banded systems using multiple experimental techniques. Different categories of banding have been suggested depending on their stability, which involve intrinsic properties of the system and streamline curvature. It has been shown qualitatively that instabilities are promoted by an increase of the surfactant concentration or of the curvature of the flow geometry, while an increase in temperature stabilizes the flow. Here, using benchmark shear banding micellar systems, we quantify, for the first time, the effect of the streamline curvature on these flow instabilities, focusing more specifically on the transition towards purely elastic turbulence. Using various optical visualizations, we identify two transitional pathways to elastic turbulence. We construct a generic state diagram in a parameter space based on the curvature ratio and the Weissenberg number. The nature -- supercritical \textit{vs} subcritical -- of the transition to elastic turbulence is discussed. The stress evolution is in favor of a change of nature from subcritical to supercritical transition as the curvature ratio increases. However we show that finite size effects cannot be neglected and may smooth artificially the stress response. Furthermore, each domain of this diagram is characterized using velocimetry measurements. Finally a scaling for the onset of elastic turbulence is determined.
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id arxiv_https___arxiv_org_abs_2509_13743
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pathways to Elastic Turbulence in Giant Micelles Through Curvature Ratios in Taylor-Couette Flow
Yang, Xiaoxiao
Marin, Darius
Py, Charlotte
Cardoso, Olivier
Lindner, Anke
Lerouge, Sandra
Soft Condensed Matter
Fluid Dynamics
In the past fifteen years, flow instabilities reminiscent of the Taylor-like instabilities driven by hoop stresses, have been observed in wormlike micelles based on surfactant molecules. In particular, purely elastic instabilities and turbulence have been shown to develop on top of shear banding, a type of flow specific to the semi-dilute and concentrated regimes. These instabilities have been identified as the origin of the large body of data showing complex spatio-temporal fluctuations, collected in shear-banded systems using multiple experimental techniques. Different categories of banding have been suggested depending on their stability, which involve intrinsic properties of the system and streamline curvature. It has been shown qualitatively that instabilities are promoted by an increase of the surfactant concentration or of the curvature of the flow geometry, while an increase in temperature stabilizes the flow. Here, using benchmark shear banding micellar systems, we quantify, for the first time, the effect of the streamline curvature on these flow instabilities, focusing more specifically on the transition towards purely elastic turbulence. Using various optical visualizations, we identify two transitional pathways to elastic turbulence. We construct a generic state diagram in a parameter space based on the curvature ratio and the Weissenberg number. The nature -- supercritical \textit{vs} subcritical -- of the transition to elastic turbulence is discussed. The stress evolution is in favor of a change of nature from subcritical to supercritical transition as the curvature ratio increases. However we show that finite size effects cannot be neglected and may smooth artificially the stress response. Furthermore, each domain of this diagram is characterized using velocimetry measurements. Finally a scaling for the onset of elastic turbulence is determined.
title Pathways to Elastic Turbulence in Giant Micelles Through Curvature Ratios in Taylor-Couette Flow
topic Soft Condensed Matter
Fluid Dynamics
url https://arxiv.org/abs/2509.13743